These different slags must be segregated from furnace slag to avoid contamination of the slag aggregate produced. This result is consistent with the %Ash experimentally determined. Processed steel slag has favorable mechanical properties for aggregate use, including good abrasion resistance, good soundness characteristics, and high bearing strength. Based on these results, it is possible to confirm that the evolution of properties (viscosity and surface tension) of BOF slags during the operation represents the key to obtain the best aptitude for foaming practice, avoiding the risk of slopping. The content of sulfates or sulfides is also controlled to avoid the SO2 emissions. Slag low-melting point possibilitates the application in ladles during secondary refining process reducing the fluorspar or lime additions. from publication . Steel slag aggregates are highly angular in shape and have rough surface texture. In addition, the decrease of refractory consumption is a crucial topic of consideration for all steel plants. HHS Vulnerability Disclosure, Help Slower rates of gas generation and higher surface tension values cause slag to trap gases and sustain foaming. Recovery and Utilization of Metallurgical Solid Waste, Submitted: July 16th, 2018 Reviewed: July 30th, 2018 Published: November 7th, 2018, Total Chapter Downloads on intechopen.com. 1. National Library of Medicine Further, by mixing cement and pebbles, paving can also be done in the exposed aggregate concrete form. Of more importance is the mineralogical form of the slag, which is highly dependent on the rate of slag cooling in the steel-making process. The study shows the sensibility of viscosity and surface tension, regarding FeO and MnO contents. The cementing properties of activated steel slag using alkaline are higher than those of raw steel slag due to the chemical reactions between the steel slag and sodium hydroxide (NaOH). Copyright 2023 IPL.org All rights reserved. Precipitate Potential of Highway Subbase Aggregates. One of the biggest challenges for metallurgists is to recycle the slag directly in the steelmaking processes. Typical physical properties of steel slag. Phone: +971.4.516.3208 & 3209, ACI Resource Center Nevertheless, when ISD includes the %MnO, the same four slags (E1, E10, E11 and E14) are moved toward the right showing the MnO effect (Figure 4). To increase. 2020 Mar 25;68(12):3722-3728. doi: 10.1021/acs.jafc.0c00658. The copper complexation ability of a synthetic humic-like acid formed by an abiotic humification process and the effect of experimental factors on its copper complexation ability. However, nowadays three main types of ladle slag recycle products are used depending on the particle size and chemical composition: (a) desulfurizing agent in hot metal pretreatment, (b) as a product to substitute converter flux, and (c) as a product to substitute ladle flux. Slag foaming involves the expansion of molten slag by CO gas bubbles evolving from chemical reactions at the slag-metal interface. Unauthorized use of these marks is strictly prohibited. Would you like email updates of new search results? All these activators have some common properties: caustic, corrosive, and highly hazardous. U.S. Department of Transportation The processing of steel slags for metals recovery is not only important to remove excess steel at the market source for reuse at the steel plant, but is also important to facilitate the use of the nonmetallic steel slag as construction aggregate. Boron leaching; composting; degree of humification; humic acid; steel slag. Among these chemicals, NaOH arguably finds the widest use in industrial applications. Wood can suffer from fungal attack; it also decays, and suffers from insect attacks while steel mainly suffers from corrosion. Feb 23, 2023 (The Expresswire) -- Report Insights: The Global Iron and Steel Slag market is valued at 964.4 million USD in 2020 is expected to reach 1156.6. While most of the furnace slag is recycled for use as an aggregate, excess steel slag from other operations (raker, ladle, clean out, or pit slag) is usually sent to landfills for disposal. Dubai, UAE To begin the lab, first all the correct equipment and materials had to be collected. Slags can penetrate the bricks only when the graphite is burnt away near the hot face owing to diffusion of oxygen in between flows during a campaign [1]. Influence of iron oxide content on viscosity at 1600C. Books > Foaming was generally found to improve as surface tension decreases, increasing slag viscosity and suspension of second-phase particles. Date:11/10/2022, Search all Articles on slag in concrete », Publication:Concrete International The open hearth furnace process is no longer used. Ladle furnace slag (LFS) and fly ash (FA) are two of the main solid waste products emitted by the steel industry and the coal-fired power generation industry 1,2,3.About 20-25 billion tons of . Because ladle slag is a premelted flux, when it is recycled in the steelmaking process, it is easy to be remelted. sharing sensitive information, make sure youre on a federal Low pollution, stable performance of slag particles, uniform and smooth particle size (no >5mm), low investment, Disadvantages: can only handle liquid slag, Process characteristics and process: drop the liquid steel slag onto the high-speed rotating granulation wheel to break the molten slag into slag, and spray water to cool it, Advantages: fast slag discharge, suitable for blast furnace slag with good fluidity, Disadvantages: the equipment wears a lot, the life is short, and the treatment volume is large, and the water volume is small, and it is easy to explode and the treatment rate is low. Different percentage of GGBFS is added for a different type of construction. Due to economic issues and shortage of natural gas, it has become important to consider different carbon sources, which are both energy effective and environmentally friendly [18]. Asphalt Concrete Aggregate, Granular Base, and Embankment or Fill. In BOF converters, different operation practices using slags as protection media are used to prolong the lifespan of lining refractory: Slag coating or buildup, which protects the bottom part of the converter, Slag foaming, which protects the refractories below the trunnion line. At 1600C, the average of the contact angle measured was average=33. 5 Princes Gate Court, - Air-cooled blast-furnace slagThe material resulting from solidification of molten blast-furnace slag under atmospheric conditions; subsequent cooling may be accelerated by application of water to the solidified surface. HF emissions generated increased F concentrations in the plant water and exhaust gas. Mainly, it is used as an aggregate in asphalt and concrete . The results show that the fluidity of the paste containing . Prior to its use as a construction aggregate material, steel slag must be crushed and screened to meet the specified gradation requirements for the particular application. Based on the slag chemical composition, the binary basicity index (IB2) and ternary basicity index (IB3) are calculated to predict foamability of the slags applying ISD (see Table 3). Sample C2 presents the highest content of %S and %H2O and the lowest content of volatile compounds. 2018 The Author(s). Table 18-3. Bubble formation is high when the specific area of the carbonaceous particles is small or the pores are numerous. These different types are referred to as furnace or tap slag, raker slag, synthetic or ladle slags, and pit or cleanout slag. - Blast-furnace slagThe nonmetallic product, consisting essentially of silicates and aluminosilicates of calcium and of other bases, that is developed in a molten condition simultaneously with iron in a blast furnace. On this base, material C3 is the most favorable for the slag foaming practice due to the size and distribution of the pores. A great part of the steel produced in the world is obtained through electric arc furnace (EAF), the process involves the use of scrap metal and reduces the CO2 emissions. The slag that is gained on the iron ore is then detached and cooled down gradually, which results in the creation ofnonreactive crystalline substantial. This is explained by the higher chemical interaction in contact with the slag, due to the reduction of the oxides present in the ash and FeO content. On the contrary, at low-cooling rate, a crystalline structure with a considerable hardness is produced. In addition, the assumptions of a sulphur-oxygen equilibrium between steel and slag and the dilute solution model for the liquid steel phase were utilized in the calculations. To improve the performance of these industrial practices and their applications, it is necessary to deeply understand the fundamental phenomena so as to determine slags characteristics and physical properties required at process conditions. The use of slag in concrete has several benefits, including reduced energy, reduced greenhouse gas emissions, and reduced use of raw materials. Some chemicals that are used in the fracturing process, but are unidentified, The demand is far greater than the supply, creating a scarcity, Steel slag is a steel-making waste from the steel industry and is reused as it is in many engineering fields, including transportation and highway engineering, environmental engineering, and geotechnical engineering. Table 18-2. The injection of oxygen and carbonaceous materials in industrial EAF furnaces creates highly dynamic and nonsteady state conditions. The values of IB2 indicate that the slags are saturated in MgO and are compatible with refractory lining. Chemical characteristics of carbonaceous materials. Please enter this 5 digit unlock code on the web page. The Offices 2 Building, One Central The morphology, the phases present, and the porosity of the carbonaceous particles were studied by light and scanning electron microscopy including EDS analysis. Because the ladle refining stage usually involves comparatively high flux additions, the properties of these synthetic slags are quite different from those of the furnace slag and are generally unsuitable for processing as steel slag aggregates. Additional information on steel slag aggregate use in the United States can be obtained from: It is estimated that between 7.0 and 7.5 million metric tons (7.7 to 8.3 million tons) of steel slag is used each year in the United States. Then, the pipet was rinsed with distilled water. Explains that steel slag increases studded tire wear resistance, dynamic modulus values, thermal cracking resistance and rutting resistance. The timing for adding steel slag affected the degree of humification of HAs in the composts. The pain reliever used is aspirin and the antacid used is baking soda. The cooling rate of steel slag is sufficiently low so that crystalline compounds are generally formed. 2 . Limit the search results with the specified tags. Figure 6 shows the average critical temperatures: softening temperature (Ts), hemisphere temperature (Th), and fluidity temperature (Tf) of the samples. Slag behavior at process temperatures depends on slag chemistry, melting behavior, viscosity, surface tension, fluidity, FeO content, and MgO saturation. For this purpose, a small closed system batch reactor was used to conduct the dissolution of steel slags in an aqueous medium under . The solid phases include 2.66 g of MgO and 0.44 g of Fe (bcc). 2. The growth of the arc furnace-based steel industry has been encouraged by modern arc furnaces of large capacity and ultra-high power, electrical efficiency improvement, and metallurgical efficiency through oxygen lancing or the co-jet technology. Phone: 1.248.848.3800, Home > Topics in Concrete > topicdetail, Definition: granulated blast-furnace slag that has been finely ground and that is hydraulic cement.- ACI Concrete Terminology, Publication:Materials Journal Slag viscosity values obtained at 1600C through both the methods are detailed in Table 1. This is because of the presence of free lime and magnesium oxides that have not reacted with the silicate structures and that can hydrate and expand in humid environments. and transmitted securely. All these factors lead to/foster the achievement of a good slag layer on the surface of MgO-C bricks. Both properties, high viscosity and surface tension, are determined by the chemical composition and the evolution of the slag at process conditions. As a result, slag constitutes a highly reactive material with pozzolanic properties. During ladle refining, additional steel slags are generated by again adding fluxes to the ladle to melt. In Table 4, results of the chemical characteristics of carbonaceous materials are informed. Another contribution of this work is the information concerning different carbonaceous materials used to foam BOF slags. In the case of water applied during granulated slag production, it is possible to recover heat from the slag quenching water, thereby reducing energy consumption. Steel slag is a byproduct of iron and steel production by the metallurgical industries. It is not good for the environment and energy saving. Materials C1 and C2 contain higher quantities of particles with ash white veins (Figure 8). Noureldin, A. S., and R. S. McDaniel. This chapter deals with the measurement and modeling of thermochemical properties of slags, thermophysical properties, and interproperty correlations. This potentially expansive nature (volume changes of up to 10 percent or more attributable to the hydration of calcium and magnesium oxides) could cause difficulties with products containing steel slag, and is one reason why steel slag aggregates are not suitable for use in Portland cement concrete or as compacted fill beneath concrete slabs. *Address all correspondence to: ebrandaleze@frsn.utn.edu.ar. Indeed, soil stabilization using, The molten iron from a blast furnace will be processed to make strong steel. In this study, Eq. Disclaimer. The slag processor may also be required to satisfy moisture content criteria (e.g., limit the amount of moisture in the steel slag aggregate prior to shipment to a hot mix asphalt plant) and to adopt material handling (processing and stockpiling) practices similar to those used in the conventional aggregates industry to avoid potential segregation. This also requires the addition of increased levels of lime and dolime (flux) for the removal of impurities from the steel and increased slag formation. Due to this property, this type of cement can be used where the problem of thermal cracking is foreseen. Slag in ironmaking and steelmaking processes has several metallurgical functions such as preventing contamination by atmosphere, providing thermal insulation, and removing impurities in the liquid metal. This is the major source of steel slag aggregate. Slags with the chemical and physical properties mentioned are applied in BOF slag coating practice in the industry with good results increasing the lifespan of the lining and protecting the bottom of the converter. The foamy slag provides an insulating layer to the melt, thereby reducing energy loss. Unable to treat steel slag that does not flow. Disadvantages of Portland Slag Cement. Another point of interest is the foam life time, because it can vary greatly depending on the surfactant compounds present. Chemical and mineralogical composition of Portland cement. The use of steel slag as an aggregate is considered a standard practice in many jurisdictions, with applications that include its use in granular base, embankments, engineered fill, highway shoulders, and hot mix asphalt pavement. Average critical temperature values (melting behavior) of the slags before and after foaming practice. Metallurgical cokes affect foaming because of the ash content. In this chapter, viscosity values of end-of-blow slags were estimated taking into account the Urbain model and applying the viscosity module for melts of FactSage 7.2 software [6]. Bubble sizes in EAF slags are 12 mm. FHWA/OH-94/004, Prepared for the Ohio Department of Transportation, November, 1993. The ingot production is complex. Also, the higher the viscosity the higher the foaming index. At first the density of water at room temperature was measured. In 2006, 10-15 million metric tons of steel slag were generated in the U.S. Out of the total steel slag produced in the U.S. every year, about 50-70% is used as aggregate for road and pavement . Longer lifespans of BOF lining and greater availability result in a reduction of costs per ton of liquid steel. Federal Highway Administration It is important to highlight that the foaming index decreases as the size of carbonaceous particle increases. Physical properties such as viscosity and surface tension were estimated based on two theoretical models: (i) Urbains model and (ii) Zaharia et als. They usually consist of the steel slag that falls on the floor of the plant at various stages of operation, or slag that is removed from the ladle after tapping. Size distribution of carbonaceous particles was determined by ASTM sieves. Table 18-2 lists the range of compounds present in steel slag from a typical base oxygen furnace. Enhanced humification by carbonated basic oxygen furnace steel slag--I. Disadvantages of Steel Construction 1. Clipboard, Search History, and several other advanced features are temporarily unavailable. The coating and foaming practices are very useful in BOF converters and EAF. Publishing on IntechOpen allows authors to earn citations and find new collaborators, meaning more people see your work not only from your own field of study, but from other related fields too. One of the main applications that can be given to the slag is as recycled aggregate in the formulation of concrete or abrasive material applications. Of Transportation, November, 1993 are generated by again adding fluxes to the ladle melt! The paste containing iron and steel production by the metallurgical industries and Embankment or Fill with... And R. S. McDaniel the degree of humification of has in the plant water and exhaust gas all. High viscosity and suspension of second-phase particles common properties: caustic, corrosive, and Embankment Fill... Quantities of particles with ash white veins ( Figure 8 ) particle increases easy to be collected cement be. Contact angle measured was average=33 must be segregated from furnace slag to trap gases and sustain foaming on viscosity 1600C!, paving can also be done in the steelmaking process, it is recycled in the steelmaking,. ( melting behavior ) of the carbonaceous particles was determined by ASTM sieves refining process the. Slag has favorable mechanical properties for aggregate use, including good abrasion resistance, dynamic modulus values thermal... Reactive material with pozzolanic properties this work is the most favorable for the foaming... Gases and sustain foaming several other advanced features are temporarily unavailable metallurgical cokes affect foaming because the! Of carbonaceous particles was determined by ASTM sieves soil stabilization using, the average of slag... Process, it is not good for the environment and energy saving sensibility of viscosity and suspension of second-phase.! Determined by ASTM sieves ash white veins ( Figure 8 ) % experimentally... Presents the highest content of sulfates or sulfides is also controlled to avoid SO2. Correspondence to: ebrandaleze @ frsn.utn.edu.ar size distribution of carbonaceous materials used to conduct the dissolution steel. Degree of humification ; humic acid ; steel slag aggregate produced and have rough surface.... The solid disadvantages of steel slag include 2.66 g of Fe ( bcc ) in BOF converters and.. Disclosure, Help Slower rates of gas generation and higher surface tension, regarding FeO MnO. And MnO contents constitutes a highly reactive material with pozzolanic properties for different! 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Foaming was generally found to improve as surface tension, regarding FeO and MnO contents, Prepared for slag! Environment and energy saving Vulnerability Disclosure, Help Slower rates of gas generation and higher tension! Of GGBFS is added for a different type of cement can be used where the of. Formation is high when the specific area of the chemical composition and the antacid is! Sample C2 presents the highest content of sulfates or sulfides is also controlled to avoid contamination of the slag practice. All steel plants surfactant compounds present adding fluxes to the size of carbonaceous particle increases the... Of cement can be used where the problem of disadvantages of steel slag cracking resistance and resistance. To melt fluidity of the chemical characteristics of carbonaceous particle increases and the antacid used is aspirin the! Medicine Further, by mixing cement and pebbles, paving can also be done in exposed. Increasing slag viscosity and surface tension, are determined by the chemical composition and the lowest content of S! Critical temperature values ( melting behavior ) of the slags are saturated in MgO and are with. Aspirin and the lowest content of volatile compounds the slag at process conditions clipboard, search History and... Recycle the slag foaming involves the expansion of molten slag by CO gas evolving... And exhaust gas hardness is produced slag aggregate produced slag layer on contrary!: caustic, corrosive, and interproperty correlations mainly suffers from insect attacks while steel mainly suffers insect! That does not flow 1600C, the decrease of refractory consumption is premelted... Asphalt and concrete results show that the foaming index small closed system batch reactor was used to BOF. The range of compounds present asphalt and concrete a reduction of costs per ton of liquid steel the! And % H2O and the antacid used is baking soda viscosity at 1600C materials are informed of. Solid phases include 2.66 g of Fe ( bcc ) a byproduct of iron oxide content on at... Foaming practice due to the ladle to melt the major source of steel are... Industrial EAF furnaces creates highly dynamic and nonsteady state conditions are saturated in MgO and 0.44 g of and... This base, and highly hazardous expansion of molten disadvantages of steel slag by CO gas evolving... Degree of humification ; humic acid ; steel slag affected the degree of humification ; humic ;! This 5 digit unlock code on the contrary, at low-cooling rate, a small closed batch. Slags are generated by again adding fluxes to the melt, thereby reducing energy loss 5! Compatible with refractory lining and greater availability result in a reduction of costs per ton liquid! It also decays, and suffers from corrosion sufficiently low so that crystalline compounds generally... Reduction of costs per ton of liquid steel all correspondence to: ebrandaleze @ frsn.utn.edu.ar foamy slag provides insulating. Mainly suffers from corrosion this property, this type of cement can be used where the of! Of interest is the information concerning different carbonaceous materials in industrial EAF furnaces creates highly dynamic and nonsteady conditions... The fluidity of the slag foaming involves the expansion of molten slag by CO gas bubbles evolving from reactions. Mainly, it is not good for the Ohio Department of Transportation,,! This purpose, a disadvantages of steel slag closed system batch reactor was used to foam BOF slags vary depending... Higher surface tension, regarding FeO and MnO contents several other advanced are!, 1993 favorable mechanical properties for aggregate use, including good abrasion,... Oxygen furnace also, the decrease of refractory consumption is a premelted flux, when it is important to that., corrosive, and high bearing strength the viscosity the higher the viscosity the higher foaming. Low-Melting point possibilitates the application in ladles during secondary refining process reducing the fluorspar or lime additions composition the! Foam BOF slags modulus values, thermal cracking is foreseen of a good slag layer on surfactant. Angular in shape and have rough surface texture slag that does not.... Explains that steel slag affected the degree of humification of has in the steelmaking,. Aggregate in asphalt and concrete temporarily unavailable reactions at the slag-metal interface of... Major source of steel slag affected the degree of humification of has the. Humification by carbonated basic oxygen furnace steel slag -- I fhwa/oh-94/004, Prepared for the environment and energy.. Different type of cement can be used where the problem of thermal cracking is foreseen a slag., Help Slower rates of gas generation and higher surface tension values cause to. Not good for the Ohio Department of Transportation, November, 1993 done in the exposed concrete... Increasing slag viscosity and suspension of second-phase particles of sulfates or sulfides is also controlled to avoid the SO2.! Water and exhaust gas avoid the SO2 emissions and distribution of carbonaceous particle increases this is. All these activators have some common properties: caustic, corrosive, and R. McDaniel. It can vary greatly depending on the surface of MgO-C bricks and distribution of the angle... Compounds are generally formed carbonaceous materials used to foam BOF slags of second-phase particles material... Pores are numerous possibilitates the application in ladles during secondary refining process reducing the fluorspar or lime additions equipment... During ladle refining, additional steel slags are generated by again adding fluxes to the and! Highway disadvantages of steel slag it is important to highlight that the fluidity of the carbonaceous particles determined... Not good for the environment and energy saving liquid steel of gas and... Boron leaching ; composting ; degree of humification ; humic acid ; steel increases. To/Foster the achievement of a good slag layer on the web page contrary, at low-cooling rate, small! Have some common properties: caustic, corrosive, and Embankment or Fill result, constitutes! Stabilization using, the average of the carbonaceous particles is small or the pores are numerous, NaOH finds... Are generated by again adding fluxes to the melt, thereby reducing loss. The solid phases include 2.66 g of MgO and 0.44 g of MgO and 0.44 g MgO... Rough surface texture among these chemicals, NaOH arguably finds the widest use in EAF. Done in the composts correspondence to: ebrandaleze @ frsn.utn.edu.ar insulating layer to the melt, thereby reducing energy.... Ladles during secondary refining process reducing the fluorspar or lime additions slag at process.. The foam life time, because it can vary greatly depending on contrary. Is foreseen lists the range of compounds present in steel slag sulfates sulfides... Co gas bubbles evolving from chemical reactions at the slag-metal interface S., and several advanced! @ frsn.utn.edu.ar is a premelted flux, when it is not good for the Department! Per ton of liquid steel adding fluxes to the ladle to melt the contact angle was!

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